Changeset 2822 in webkit for trunk/JavaScriptCore/kjs/collector.cpp

Timestamp:

Nov 22, 2002, 12:13:09 AM (23 years ago)

Author:

mjs

Message:

• a simple change for .4% gain on ibench - instead of unmarking all objects at the start of collection, instead unmark as part of the sweep phase

• kjs/collector.cpp: (Collector::collect): Remove separate unmarking pass and instead unmark the objects that don't get collected during the sweep phase.

File:

• trunk/JavaScriptCore/kjs/collector.cpp (modified) (5 diffs)

trunk/JavaScriptCore/kjs/collector.cpp

@@ -161 +161 @@
 {
   bool deleted = false;
-  // MARK: first unmark everything
-  for (int block = 0; block < heap.usedBlocks; block++) {
-    for (int cell = 0; cell < CELLS_PER_BLOCK; cell++) {
-      ((ValueImp *)(heap.blocks[block]->cells + cell))->_flags &= ~ValueImp::VI_MARKED;
-    }
-  }
-  for (int cell = 0; cell < heap.usedOversizeCells; cell++) {
-    ((ValueImp *)heap.oversizeCells[cell])->_flags &= ~ValueImp::VI_MARKED;
-  }
-  
-  // mark all referenced objects recursively
+
+  // MARK: first mark all referenced objects recursively
   // starting out from the set of root objects
   if (InterpreterImp::s_hook) {
@@ -205 +196 @@
     }
   }
-  
-  // SWEEP: delete everything with a zero refcount (garbage)
+
+  // SWEEP: delete everything with a zero refcount (garbage) and unmark everything else
   
   int emptyBlocks = 0;
@@ -214 +205 @@
       uint32_t word = heap.blocks[block]->bitmap[wordInBitmap];
       for (int bitInWord = 0; bitInWord < BITS_PER_WORD; bitInWord++) {
+        
+        if (word & (1 << bitInWord)) {
         ValueImp *imp = (ValueImp *)(heap.blocks[block]->cells + BITS_PER_WORD * wordInBitmap + bitInWord);
-        
-        if ((word & (1 << bitInWord)) &&
-            !imp->refcount && imp->_flags == (ValueImp::VI_GCALLOWED | ValueImp::VI_CREATED)) {
-          // emulate destructing part of 'operator delete()'
-          //fprintf( stderr, "Collector::deleting ValueImp %p (%s)\n", (void*)imp, typeid(*imp).name());
-          imp->~ValueImp();
-          heap.blocks[block]->bitmap[wordInBitmap] &= ~(1 << bitInWord);
-          heap.blocks[block]->usedCells--;
-          heap.numLiveObjects--;
-          deleted = true;
+          if (!imp->refcount && imp->_flags == (ValueImp::VI_GCALLOWED | ValueImp::VI_CREATED)) {
+            //fprintf( stderr, "Collector::deleting ValueImp %p (%s)\n", (void*)imp, typeid(*imp).name());
+            // emulate destructing part of 'operator delete()'
+            imp->~ValueImp();
+            heap.blocks[block]->bitmap[wordInBitmap] &= ~(1 << bitInWord);
+            heap.blocks[block]->usedCells--;
+            heap.numLiveObjects--;
+            deleted = true;
+          } else {
+            imp->_flags &= ~ValueImp::VI_MARKED;
+          }
         }
       }
@@ -246 +240 @@
     }
   }
-
 
   
@@ -272 +265 @@
 
     } else {
+      imp->_flags &= ~ValueImp::VI_MARKED;
       cell++;
     }